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.TH MKDIR 2 "Sep 24, 2016"
.SH NAME
mkdir, mkdirat \- make a directory
.SH SYNOPSIS
.LP
.nf
#include <sys/types.h>
#include <sys/stat.h>

\fBint\fR \fBmkdir\fR(\fBconst char *\fR\fIpath\fR, \fBmode_t\fR \fImode\fR);
.fi
.LP
.nf
\fBint\fR \fBmkdirat\fR(\fBint\fR \fIfd\fR, \fBconst char *\fR\fIpath\fR, \fBmode_t\fR \fImode\fR);
.fi

.SH DESCRIPTION
.LP
The \fBmkdir()\fR and \fBmkdirat()\fR functions create a new directory named by
the path name pointed to by \fIpath\fR. The mode of the new directory is
initialized from \fImode\fR (see \fBchmod\fR(2) for values of mode). The
protection part of the \fImode\fR argument is modified by the process's file
creation mask (see \fBumask\fR(2)).
.sp
.LP
The directory's owner \fBID\fR is set to the process's effective user ID. The
directory's group \fBID\fR is set to the process's effective group ID, or if
the \fBS_ISGID\fR bit is set in the parent directory, then the group \fBID\fR
of the directory is inherited from the parent.  The \fBS_ISGID\fR bit of the
new directory is inherited from the parent directory.
.sp
.LP
If \fIpath\fR names a symbolic link, \fBmkdir()\fR and \fBmkdirat()\fR fail and
set errno to \fBEEXIST\fR.
.sp
.LP
The newly created directory is empty with the exception of entries for itself
(\fB\&.\fR) and its parent directory (\fB\&..\fR).
.sp
.LP
The \fBmkdirat()\fR function behaves similarly to \fBmkdir()\fR; however, if
\fIpath\fR is a relative path, then the directory represented by \fBfd\fR is
used as the starting point for resolving \fIpath\fR. To use the processes
current working directory, \fIfd\fR may be set to the value \fBAT_FDCWD\fR.
.sp
.LP
Upon successful completion, \fBmkdir()\fR and \fBmkdirat()\fR mark for update
the \fBst_atime\fR, \fBst_ctime\fR and \fBst_mtime\fR fields of the directory.
Also, the \fBst_ctime\fR and \fBst_mtime\fR fields of the directory that
contains the new entry are marked for update.
.SH RETURN VALUES
.LP
Upon successful completion, \fB0\fR is returned. Otherwise, \fB\(mi1\fR is
returned, no directory is created, and \fBerrno\fR is set to indicate the
error.
.SH ERRORS
.LP
The \fBmkdir()\fR and \fBmkdirat()\fR functions will fail if:
.sp
.ne 2
.na
\fB\fBEACCES\fR\fR
.ad
.RS 16n
Either a component of the path prefix denies search permission or write
permission is denied on the parent directory of the directory to be created.
.RE

.sp
.ne 2
.na
\fB\fBEDQUOT\fR\fR
.ad
.RS 16n
The directory where the new file entry is being placed cannot be extended
because the user's quota of disk blocks on that file system has been exhausted;
the new directory cannot be created because the user's quota of disk blocks on
that file system has been exhausted; or the user's quota of inodes on the file
system where the file is being created has been exhausted.
.RE

.sp
.ne 2
.na
\fB\fBEEXIST\fR\fR
.ad
.RS 16n
The named file already exists.
.RE

.sp
.ne 2
.na
\fB\fBEFAULT\fR\fR
.ad
.RS 16n
The \fIpath\fR argument points to an illegal address.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 16n
An attempt was made to create an extended attribute that is a directory.
.RE

.sp
.ne 2
.na
\fB\fBEIO\fR\fR
.ad
.RS 16n
An I/O error has occurred while accessing the file system.
.RE

.sp
.ne 2
.na
\fB\fBEILSEQ\fR\fR
.ad
.RS 16n
The path argument includes non-UTF8 characters and the file system accepts only
file names where all characters are part of the UTF-8 character codeset.
.RE

.sp
.ne 2
.na
\fB\fBELOOP\fR\fR
.ad
.RS 16n
Too many symbolic links were encountered in translating \fIpath\fR, or a loop
exists in symbolic links encountered during resolution of \fIpath\fR
.RE

.sp
.ne 2
.na
\fB\fBEMLINK\fR\fR
.ad
.RS 16n
The maximum number of links to the parent directory would be exceeded.
.RE

.sp
.ne 2
.na
\fB\fBENAMETOOLONG\fR\fR
.ad
.RS 16n
The length of the \fIpath\fR argument exceeds \fBPATH_MAX\fR, or the length of
a \fIpath\fR component exceeds \fBNAME_MAX\fR while \fB_POSIX_NO_TRUNC\fR is in
effect.
.RE

.sp
.ne 2
.na
\fB\fBENOENT\fR\fR
.ad
.RS 16n
A component of the path prefix does not exist or is a null pathname.
.RE

.sp
.ne 2
.na
\fB\fBENOLINK\fR\fR
.ad
.RS 16n
The \fIpath\fR argument points to a remote machine and the link to that machine
is no longer active.
.RE

.sp
.ne 2
.na
\fB\fBENOSPC\fR\fR
.ad
.RS 16n
No free space is available on the device containing the directory.
.RE

.sp
.ne 2
.na
\fB\fBENOTDIR\fR\fR
.ad
.RS 16n
A component of the path prefix is not a directory. For \fBlinkat()\fR, if
\fIpath\fR is a relative path and \fIfd\fR refers to a valid file descriptor
which is not a directory.
.RE

.sp
.ne 2
.na
\fB\fBEROFS\fR\fR
.ad
.RS 16n
The path prefix resides on a read-only file system.
.RE

.sp
.LP
The \fBmkdirat()\fR function will fail if:
.sp
.ne 2
.na
.B EBADF
.ad
.RS 16n
The path \fIpath\fR is a relative path and \fIfd\fR is not a valid open file
descriptor or the value \fBAT_FDCWD\fR.
.RE

.sp
.LP
The \fBmkdir()\fR function may fail if:
.sp
.ne 2
.na
\fB\fBENAMETOOLONG\fR\fR
.ad
.RS 16n
As a result of encountering a symbolic link in resolution of the \fIpath\fR
argument, the length of the substituted pathname string exceeded
{\fBPATH_MAX\fR}.
.RE

.SH EXAMPLES
.LP
\fBExample 1 \fRCreate a directory.
.sp
.LP
The following example demonstrates how to create a directory named
\fB/home/cnd/mod1\fR, with read, write, and search permissions for owner and
group, and with read and search permissions for others.

.sp
.in +2
.nf
#include <sys/types.h>
#include <sys/stat.h>
int status;
\&...
status = mkdir("/home/cnd/mod1",
     S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
.fi
.in -2

.SH ATTRIBUTES
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	Async-Signal-Safe
.TE

.SH SEE ALSO
.LP
.BR chmod (2),
.BR mknod (2),
.BR umask (2),
.BR mkdirp (3GEN),
.BR stat.h (3HEAD),
.BR attributes (7),
.BR standards (7)
